This invention relates to an engine, transmission assembly for a vehicle and more particularly to an improved, simplified casting construction for such an assembly.
It is well known in motorcycle and other small vehicles to employ a power unit for driving the vehicle that consists of a combined internal combustion engine and change speed transmission. Conventionally, the change speed transmission is mounted within the crank case of the engine and serves to provide the source of mode of power for the wheels. Although a wide variety of arrangements have been proposed for this purpose, the provision of not only a crankcase and crankshaft support but also the support for the primary and secondary shafts of the transmission and the associated shifting mechanism gives rise to considerable assembly problems. Although it is desirable to maintain a relatively small number of pieces, the lesser the number of pieces the more difficult the assembly will be. Also, it is essential to ensure that the rotational axes of the shafts are well supported and well located so as to avoid problems. With prior art construction, it has not always been possible to meet these objectives.
It is, therefore, a principal object of this invention to provide an improved and simplified, combined engine transmission assembly for powering a vehicle and one which simplifies servicing, is rigid and strong.
It is a further object of this invention to provide an engine transmission assembly that is made up of a relatively small number of pieces and yet which affords ease of assembly of the components and ensures accurate location of all shaft rotational axis.
It is a further object of this invention to provide an improved and simplified casting assembly for an engine transmission assembly for powering a vehicle embodying only three pieces and in which all of the shafts or a majority of the shafts are supported at parting lines between the pieces.